Light-sensitive diazotype film and method of making and using same

ABSTRACT

There is disclosed herein a method of making a light-sensitive diazotype film adapted for the development of azo dye images thereon by using an alkaline liquid developer. The method of making the diazotype film produces a porous surface of the film substrate by coating a sub-layer composition comprising a filmforming cellulose ester, a volatile water miscible organic solvent, and an aqueous solution of an inorganic perchlorate onto the film substrate which is then overcoated with a lightsensitive diazotype coating formulation.

United States Patent Kumins Oct. 14, 1975 [54] LIGHT-SENSITIVE DIAZOTYPE FILM AND 3,733,215 5/1973 Van Paesschen 96/87 R METHOD OF MAKING AND USING SAME FOREIGN PATENTS OR APPLICATIONS Inventor: Charles Kumins, Gates Mills, 699,052 10 1953 United Kingdom 96 75 Ohio 711,390 6/1954 United Kingdom 96/75 892,882 4/1962 United Kingdom 96/75 [73] Asslgnee- F' Multlgmph 1,128,837 10 1968 United Kingdom 96/75 Corporation, Cleveland, 01110 22 F d Ma 4 1974 OTHER PUBLICATIONS 1 Chemical Abstracts, 1968, V01. 69, 7842611. [21] App]. No.1 447,743

Primary ExaminerCharles L. Bowers, Jr.

[52] US. Cl 96/49; 96/75; 96/87 R;

96/91 R; 427/341; 427/415; 428/262 ABSTRACT 1 f 603C (303C (303C 5/34 There is disclosed herein a method of making a light- [58] Fleld of Search 96/75, 87 R, 49. 91 R; sensitive diazotype fil adapted f the development 117/34 161 C 166 of azo dye images thereon by using an alkaline liquid developer. The method of making the diazotype film 1 References Clted produces a porous surface of the film substrate by UNITED STATES PATENTS coating a sub-layer composition comprising a film- 2,474,700 6/1949 Slifkin 96/75 forming cellulose ester, a volatile Water miscible 2,873,207 2 1959 Weegar et a1 96/75 x ga nt, d an aq us s lution of an inorganic 2,968,581 l/l96l Kress 117/166 X perchlorate onto the film substrate which is then over- 3,353,934 1967 d m 96/75 X coated with a light-sensitive diazotype coating formu- 3,460,943 8/1969 Welch 96/75 latim 3,627,563 12/1971 Bollen et aL... 96/75 X 3,704,162 11/1972 Oshibuchi et a1. 96/75 x 18 Cla1ms,No Drawings LIGHT-SENSITIVE DIAZOTYPE FILM AND METHOD OF MAKING AND USING SAME BACKGROUND OF THE INVENTION This invention relates to the diazotype reproducing art, and more particularly, relates to an improved lightsensitive diazotype film adapted for the development of azo-dye images thereon through the direct application of alkaline liquid developers.

As is well known in the art, diazotype reproduction systems are based on the ability of a light-sensitive diazonium salt to form azo-dye images with coupling ma terial under controlled pH conditions. With the advent of the new and improved diazotype developing process disclosed in U.S. Pat. No. 3,446,620, it became possible to develop two-component diazotype materials through the direct application of small quantities of a high-concentration alkaline liquid developer. The process can be successfully utilized with a wide range of light-sensitive diazotype materials. For example, such light-sensitive materials may be prepared using paper substrates, cloths, as well as plastic film bases or substrates. However, it has been found that the development of such light-sensitive materials where the substrate is a plastic film, requires special care and handling through the development process for the reason that difficulty is encountered in uniformly wetting the surface with the alkaline material. A diazotype copy material which is non-uniformly wetted with the alkaline developer will produce an azo-dye image correspondingly lacking in uniform color development.

The present invention is concerned with the production of an improved light-sensitive diazotype material prepared on a film substrate and the method of using such a film in order to produce a diazotype copy which is uniformly wetted by the alkaline developer materials. This is accomplished by providing a film with a uniquely porous surface which readily and uniformly absorbs the alkaline developer materials.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide an improved light-sensitive diazotype material having a film substrate.

It is a further object of this invention to provide an improved diazotype copying material having a film substrate with a porous surface which is uniformly receptive to alkaline developer materials.

It is a still further object of this invention to provide an improved method of developing a diazotype copying material having a film substrate wherein the film is treated to provide it with a porous surface which is readily wettable by alkaline developing materials, resulting in a visible image of uniform intensity. These and other objects and advantages of the invention will become apparent from the following detailed description thereof which includes the best mode presently contemplated for practicing the invention.

DETAILED DESCRIPTION In accordance with one aspect of the invention, there is provided an improved diazotype copying material comprising:

a. a film substrate or base support;

b. a sub-layer applied to the film, said sub-layer having a composition comprising a film-forming cellulose ester, a volatile water miscible organic solvent, and an aqueous solution of an inorganic perchlorate;

c. a light-sensitive sensitizing composition comprising a light-sensitive diazonium salt applied to the sublayer.

In accordance with another aspect of the invention. there is provided a method of developing a diazotype copying material having a film substrate, comprising the steps (a) through (c) described above in combination with the additional steps of:

d. forming a latent image by exposing the copying material to an actinic radiation pattern corresponding to light and dark areas of a graphic original to be reproduced; and

e. contacting the copying material with a liquid alkaline developer composition to convert the latent image to a visible image.

In preparing the light-sensitive diazotype film of the instant invention, the base support is a polyester material such as heat set and biaxially oriented linear terephthalic acid-ethylene glycol polyester which is sold under the trademark Mylar. The thickness of the substrate to be utilized in the instant invention may be in the range of from 0.5 to l0 microns in thickness. the preferred range being from 1 to 5 microns.

The subcoating formulation which is applied to the polyester film, in general, comprises a cellulose ester dissolved in a suitable solvent and which includes as the active ingredient an inorganic perchlorate compound. The solvent systemincludes both a true solvent for the cellulose acetate such as, for example, acetone having a high vapor pressure and water which has a low vapor pressure. The evaporation of the high vapor pressure solvent component leaves behind a solvent system rich in water causing the polymer to precipitate from the solution. In the presence of the inorganic perchlorate, the precipitated film is rendered porous. The application of the cellulose ester solution to the surface of the base support provides a layer thereon which has the property of having a suitable porosity permitting the penetration therethrough of water as well as the organic amine-type developer materials.

In preparing the sublayer coating formulation, a cellulose film forming material is employed, such as:

nitro cellulose, ethyl cellulose, cellulose acetate,

cellulose acetate butyrate, cellulose acetate propionate,

the preferred material being cellulose acetate. Suitable sublayer formulations may contain in the range of from 15 to 35% by weight of the cellulose ester, the preferred range being between 20 and 30% by weight. The cellulose ester is dissolved in a suitable solvent such as acetone, methyl ethyl ketone, ethyl acetate, methyl isobutyl ketone, or toluene; the amount of such solvent being in the range of 50 to by weight of the sublayer formulation.

To the solvent solution of the cellulose ester is then added the inorganic perchlorate material dissolved in water. Either sodium or magnesium perchlorate may be used in amounts ranging from 0.5 to 3.5% by weight of the sublayer formulation. The amount of water in which the perchlorate is dissolved may be in the range of 5 to 15% by weight of the sublayer formulation. To the perchlorate solution is added a small amount of concentrated hydrochloric acid which represents in the range of from 0.2 to 0.5% by weight of the coating formulation. The purpose of adding the hydrochloric acid is to cause a reaction between the magnesium perchlorate and the concentrated hydrochloric acid to result in formation of perchloric acid which, together with the EXAMPLE 4 A polyester base film was coated with the following sublayer formulation in accordance with the general magnesium perchlorate is essential to the formation of 5 Procedures Set fort in Example the porous sublayer.

EXAMPLE I A specific combination of the sublayer formulation useful in the practice of the present invention is as follows:

acetone: 69.5 grams cellulose acetate: 23.2 grams water: 5.5 grams magnesium perchlorate: l.7 grams hydrochloric acid (concentrated) 0 3 grams The foregoing composition was successfully used in treating linear terephthalic acid-ethylene glycol polyester, such as sold under the trademark Melinex, available from the Imperial Chemical Industries Corporation.

The sublayer formulation was applied to the polyester film in an amount of about grams per square meter. It will be appreciated that the loading of the sublayer solution to the film will depend a great deal on the viscosity and concentration of the cellulose ester in the coating formulation. Hence, the useful coating range is from 5 grams to grams per square meter, the preferred range being from 7 grams to 10 grams per square meter.

After the coating formulation has been applied, it is subjected to forced air drying so as to evaporate the various solvents leaving a dry coating having a thickness of about 0.2 mills. Understandably, the thickness of the sublayer is not critical and could vary anywhere from 0.15 mills to 1.0 mills in thickness, the preferred range being from 0.2 to 0.3 mills.

Any conventional coating method may be employed for applying the sublayer formulation. The aforementioned coating formulation was applied with a meniscus coater. Other coating apparatus such as dip coating systems may be employed.

EXAMPLE 2 A sublayer formulation is applied to a polyester film following the general procedure of Example 1, using the following formulation:

acetone: 60 grams cellulose acetate butyrate: 30 grams water: 7 grams magnesium perchlorate: 2.5 grams hydrochloric acid (concentrated) 0.5 grams EXAMPLE 3 The sublayer formulation of this example follows the general procedure of Example 1 with the exception that the following formulation was employed:

methyl ethyl ketone: 55 grams cellulose acetate propionate: 35 grams water: 8 grams magnesium perchlorate: l.6 grams hydrochloric acid (concentrated) .3 grams 7 acetone: 19 grams cellulose acetate: 35 grams methyl ethyl ketone: 39 grams water: 5 grams sodium perchlorate: 1.5 grams hydrochloric acid (concentrated) 0.5 grams To complete the light-sensitive diazotype films of the instant invention, it is necessary to next apply to the sublayer carrying the film substrate the light-sensitive diazotype solution. in general, the conventional twocomponent diazotype materials are suitable. As is well known in this art, such two-component sensitizing solutions contain both the diazonium salt and the couplers in the same layer which is stabilized against precoupling by the inclusion therein of an acid component in order to maintain the pH below the coupling theshold level.

In accordance with the preferred embodiment of the invention, a two-component sensitizing composition is employed. Suitable diazonium salts include those obtained by the diazontization of the following amines:

p-amino-N,N-diethylaniline p-amino-N-ethylaniline p-amino-N-ethyl-N-hydroxyethylaniline p-amino-N-methyl-Nhydroxyethylaniline p-amino-N,N-di-B-hydroxyethylaniline p-amino-m-ethoxy-N, N-diethylaniline p-amino-N-ethyl-O-toluidine p-amino-N-ethyl-m-toluidine p-amino-N, N-diethyl-m-toluidine p-amino-N-ethyl-N-B-hydroxyethyl-m-toluidine N-p-aminophenylmorpholine l-amino-2,5-diethoxy-4-morpholinobenzene Representative couplers which may be used in combination with the foregoing and other diazonium salts include:

resorcinol, acetoacetanilide, 4-chlororesorcinol,

diresorcinol, diacetoacetylethylenediamine,

aminoethylethanolamine amide of 3-hydroxy-2 naphthoic acid, 2,3-dihydroxy-6-naphthalene sulfonic acid (sodium salt).

The following is a typical formulation for sensitizing the films prepared in the foregoing examples:

EXAMPLE 5 water: 600 ccs diethylene glycol: 40 ccs citric acid: 20 grams zinc chloride: 50 grams isopropyl alcohol: 10 ccs 2.3-dihydroxynaphthalene-6- sulfonic acid (sodium salt): 40 grams p-Diazo-N, N-diethylaniline zinc chloride: 15 grams Thiourea: 30 grams water to make 1,000 ccs The formulation was coated on the film prepared in Example I at a rate resulting in the application of 15 grams of the solution per square meter.

It has been found that the light-sensitive diazotype films of this invention give high quality performance when developed using the conventional ammonia gas techniques. However, as set forth earlier in this description of the invention, it is particularly adapted to function under conditions of development where small quantities of high concentration liquid alkaline developers are applied to the surface.

Suitable developers which may be used as liquid alkaline developers are compositions containing at least 20% by weight of a liquid amine component such as an aliphatic amine, the amine component having the general formula:

wherein R, is alkanol (hydroxyalkyl), cycloalkyl or aralkyl, and R and R are hydrogen, alkyl, alkanol (hydroxyalkyl), cycloalkyl or aralkyl. Heterocyclic amines such as morpholine and piperidine can also be used as the amine component. Preferred are the alkanolamines of the general formula:

wherein R and R are the same or different alkyl or hydroxyalkyl substituents or are hydrogen, X is hydrogen, lower alkyl or lower hydroxyalkyl, and n is an integer from 2 to 4, inclusive.

Although the developer compositions consisting of liquid amines are contemplated, the developer compositions will preferably contain a diluent present in an amount within the range of about 20 to 80 weight percent, and preferably from about 40 to about 60 weight percent. Suitable diluents may be selected from the group consisting of a polyhydric alcohol, such as a glycol, or a glycol ether, or a monohydric alcohol. Specific examples of diluents used in the practice of the present invention include hexylene glycol, propylene glycol, glycerine, ethylene glycol, monoethyl ether, diethylene glycol, monoethyl ether, 2-ethylhexanol, and isoctyl alcohol.

Specific developer compositions useful in the practice of the present invention include the following:

EXAMPLE 6 monoethanolamines: 60% hexylene glycol: 20% water: 20%

EXAMPLE 7 2(2-aminoethoxy)ethanol: 40% hexylene glycol: 25% diethylene glycol: 35%

EXAMPLE 8 morpholine: 5% monoethanolamines: 10% dimethylethanolamine: 5% pentoxol solvent: Cellosolve: 35% hexylene glycol:

EXAMPLE 9 diethylenetriamine: 50% hexylene glycol: 25% Cellosolve: 25%

EXAMPLE l0 cyclohexolamine: 50% diethylene glycol: 25% Cellosolve: 25%

The amount of developer deposited on the sensitizing composition should fall within the range of about 0.5 to about 3.0 grams per square meter, and preferably within the range of about 0.75 to about 2.0 grams per square meter.

The light-sensitive diazotype films of this invention have the unique property of being easily and conveniently developed using the developing solutions of the instant invention under conditions where verysmall quantities of the developer are applied to the surface so that the film emerges from the developing process in a nearly dry condition. The small amounts of developer applied are such that they are readily absorbed into the porous layer so as to obviate the need for a special drying step. The film emerges from the developing step without experiencing any transfer or deposit of the developer material onto ones hands, clothes, or other materials with which the developed film is brought into contact. Further, the film reproduction is developed with suitably dense azo-dye images, attaining their maximum density within several minutes after development.

Having thus described the invention, what is claimed l. A method of making a diazotype copying material having a polyester film substrate comprising the steps of:

a. coating said film with a composition comprising a film forming cellulose ester in the range of from about 15 to 35% by weight, a volatile, water miscible organic solvent, and an aqueous solution containing in the range of from about 0.5 to 3.5% by weight of an inorganic perchlorate selected from the group consisting of sodium and magnesium perchlorate to form perchloric acid;

b. removing a portion only of said solvent by evaporation;

c. contacting said coating with water to remove the remainder of said solvent and to extract at least a portion of said inorganic perchlorate;

d. drying the residue of said coating, thereby providing said film with a porous surface; and

e. applying to said porous surface a sensitizing composition comprising a light sensitive diazonium salt.

2. The method defined in claim 1 wherein said cellulose ester is cellulose acetate and said solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, acetone and methyl ethyl ketone.

3. The method defined in claim 2 wherein said inorganic perchlorate is magnesium perchlorate.

4. The method defined in claim 1 wherein said film is formed of a polyester resin.

5. The method defined in claim 1 wherein said sensitizing composition further comprises a coupler ingredient for said diazonium salt, and an acid ingredient for maintaining the pH at a level below which the diazonium salt and coupler react.

6. A method of developing a diazotype copying material having a polyester film substrate, comprising the steps of;

a. coating said film with a composition comprising a film-forming cellulose ester in the range of from about 15 to 35% by weight, a volatile, water miscible organic solvent, and an aqueous solution containing in the range of about 0.5 to 3.5% by weight of an inorganic perchlorate selected from the group of sodium or magnesium perchlorate to form perchloric acid;

b. removing a portion only of said solvent by evaporation;

c. contacting said coating with water to remove the remainder of said solvent and to extract at least a portion of said inorganic perchlorate;

d. drying the residue of said coating, thereby providing said film with a porous surface;

e. applying to said porous surface a sensitizing composition comprising a light sensitive diazonium salt;

f. forming a latent image by exposing said copying material to an actinic radiation pattern corresponding to light and dark areas of the original being copied; and

g. contacting said copying material with a liquid alkaline developer composition to convert said latent image to a visible azo-dye image.

7. The method defined in claim 6 wherein said cellulose ester is cellulose acetate and said solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, acetone and methyl ethyl ketone.

8. The method defined in claim 6 wherein said inorganic perchlorate is magnesium perchlorate.

9. The method defined in claim 6 wherein said film is formed of a polyester resin.

10. The method defined in claim 6 wherein said sensitizing composition further comprises a coupler ingredient for said diazonium salt, and an acid ingredient for maintaining the pH at a level below which the diazonium salt and coupler react.

11. The method defined in claim 10 wherein said liquid alkaline developer composition comprises at least by weight of an organic amine selected from the group consisting of morpholine, piperidine, lower alkylmorpholine, lower alkylpiperidine, and amines of the formula wherein R is selected from the group consisting of alkyl, cycloalkyl, alkyl-aryl, alkylol, alkoxy and polyols, and R and R are selected from the group consisting of R and hydrogen.

12. The method defined in claim 11 wherein said liquid developer composition is applied to said sensitizing composition at a rate within the range of 0.75 to 2.0 gm/m of surface.

13. A light sensitive diazotype film comprising a polyester base support. a porous subcoat layer formed by applying a coating formulation comprising a filmforming cellulose ester in the range of from about 15 to 35% by weight, a volatile water-miscible organic solvent and an aqueous solution containing in the range of about 0.5 to 3.5% by weight of an inorganic perchlorate selected from the group consisting of sodium and magnesium perchlorate to form perchloric acid, which formulation forms a porous subcoat layer upon the evaporation of the volatile solvents; and a light sensitive two-component diazotype coating applied to said sublayer.

14. The light sensitive diazotpye film as claimed in claim 13 wherein said cellulose ester is cellulose acetate.

15. The light sensitive diazotype film as claimed in claim 13 wherein said cellulose ester is cellulose acetate butyrate.

16. The light sensitive diazotype film as claimed in claim 13 wherein said cellulose ester is cellulose acetate propionate.

17. The light sensitive diazotype film as claimed in claim 13 wherein said inorganic perchlorate is magnesium perchlorate.

18. The light sensitive diazotype film as claimed in claim 13 wherein said inorganic perchlorate is sodium perchlorate. 

1. A METHOD OF MAKING A DIAZOTYPE COPYING MATERIAL HAVING A POLYESTER FILM SUBSTRATE COMPRISING THE STEPS OF: A. COATING SAID FILM WITH A COMPOSITION COMPRISING A FILM FORMING CELLULOSE ESTER IN THE RANGE OF FROM ABOUT 15 TO 35% BY WEIGHT, A VOLATILE, WATER MICIBLE ORGANIC SOLVENT, AND AN AQUEOUS SOLUTION CONTAINING IN THE RANGE OF FROM ABOUT 0.5 TO 3.5% BY WEIGHT OF AN INORGANIC PERCHLORATE SELECTED FROM THE GROUP CONSISTING OF SODIUM AND MAGNESIUM PERCHLORATE TO FORM PERCHLORIC ACID, B. REMOVING A PORTION ONLY OF SAID SOLVENT BY EVAPORATION, C. CONTACTING SAID COATING WITH WATER TO REMOVE THE REMAINDER OF SAID SOLVENT AND TO EXTRACT AT LEAST A PORTION OF SAID INORGANIC PERCHLORATE, D. DRYING THE RESIDUE OF SAID COATING, THEREBY PROVIDING SAID FILM WITH A POROUS SURFACE, AND E. APPLYING TO SAID POROUS SURFACE A SENSITIZINGG COMPOSITION COMPRISING A LIGHT SENSITIVE DIAZONIUM SALT.
 2. The method defined in claim 1 wherein said cellulose ester is cellulose acetate and said solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, acetone and methyl ethyl ketone.
 3. The method defined in claim 2 wherein said inorganic perchlorate is magnesium perchlorate.
 4. The method defined in claim 1 wherein said film is formed of a polyester resin.
 5. The method defined in claim 1 wherein said sensitizing composition further comprises a coupler ingredient for said diazonium salt, and an acid ingredient for maintaining the pH at a level below which the diazonium salt and coupler react.
 6. A METHOD OF DEVELOPING A DIAZOTYPE COPYING MATERIAL HAVING A POLYESTER FILM SUBSTRATE, COMPRISING THE STEPS OF: A. COATING SAID FILM WITH A COMPOSITION COMPRISING A FILMFORMING CELLULOSE ESTER IN THE RANGE OF FROM ABOUT 15 TO 35% BY WEIGHT, A VOLATILE, WATER MISCIBLE ORGANIC SOLVENT, AND AN AQUEOUS SOLUTION CONTAINING IN THE RANGE OF ABOUT 0.5 TO 3.5% BY WEIGHT OF AN INORGANIC PERCHLORATE SELECTED FROM THE GROUP OF SODIUM OR MAGNESIUM PERCHLORATE TO FORM PERCHLORIC ACID, B. REMOVING A PORTION ONLY OF SAID SOLVENT BY EVAPORATION, C. CONTACTING SAID COATING WITH WATER TO REMOVE THE REMAINDER OF SAID SOLVENT AND TO EXTRACT AT LEAST A PORTION OF SAID INORGANIC PERCHLORATE, D. DRYING THE RESIDUE OF SAID COATING, THEREBY PROVIDING SAID FILM WITH A POROUS SURFACE, E. APPLYING TO SAID POROUS SURFACE A SENSITIZINGG COMPOSITION COMPRISING A LIGHT SENSITIVE DIAZONIUM SALT, F. FORMING A LATENT IMAGE BY EXPOSING SAID COPYING MATERIAL TO AN ACTINIC RADIATION PATTERN CORRESPONDING TO LIGHT AND DARK AREAS OF THE ORIGINAL BEING COPIED, AND G. CONTACTING SAID COPYING MATERIAL WITH A LIQUID ALKALINE DEVELOPER COMPOSITION TO CONVERT SAID LATENT IMAGE TO A VISIBLE AZO-DYE IMAGE.
 7. The method defined in claim 6 wherein said cellulose ester is cellulose acetate and said solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, acetone and methyl ethyl ketone.
 8. The method defined in claim 6 wherein said inorganic perchlorate is magnesium perchlorate.
 9. The method defined in claim 6 wherein said film is formed of a polyester resin.
 10. The method defined in claim 6 wherein said sensitizing composition further comprises a coupler ingredient for said diazonium salt, and an acid ingredient for maintaining the pH at a level below which the diazonium salt and coupler react.
 11. The method defined in claim 10 wherein said liquid alkaline developer composition comprises at least 20% by weight of an organic amine selected from the group consisting of morpholine, piperidine, lower alkylmorpholine, lower alkylpiperidine, and amines of the formula
 12. The method defined in claim 11 wherein said liquid developer composition is applied to said sensitizing composition at a rate within the range of 0.75 to 2.0 gm/m2 of surface.
 13. A LIGHT SENSITIVE DIAZOTYPE FILM COMPRISING A POLYESTER BASE SUPPORT, A POROUS SUBCOAT LAYER FORMED BY APPLYING A COATING FORMULATION COMPRISING A FILM-FORMING CELLULOSE ESTER IN THE RANGE OF FROM ABOUT 15 TO 35% BY WEIGHT, A VOLATILE WATER-MISCIBLE ORGANIC SOLVENT AND AN AQUEOUS SOLUTION CONTAINING IN THE RANGE OF ABOUT 0.5 TO 3.5% BY WEIGHT OF AN INORGANIC PERCHLORATE SELECTED FROM THE GROUP CONSISTING OF SODIUM AND MAGNESIUM PERCHLORATE TO FORM PERCHLORIC ACID, WHICH FORMULATION FORMS A POROUS SUBCOAT LAYER UPON THE EVAPORATION OF THE VOLATILE SOLVENTS, AND A LIGHT SENSITIVE TOWCOMPONENT DIAZOTYPE COATING APPLIED TO SAID SYBLAYER.
 14. The light sensitive diazotpye film as claimed in claim 13 wherein said cellulose ester is cellulose acetate.
 15. The light sensitive diazotype film as claimed in claim 13 wherein said cellulose ester is cellulose acetate butyrate.
 16. The light sensitive diazotype film as claimed in claim 13 wherein said cellulose ester is cellulose acetate propionate.
 17. The light sensitive diazotype film as claimed in claim 13 wherein said inorganic perchlorate is magnesium perchlorate.
 18. The light sensitive diazotype film as claimed in claim 13 wherein said inorganic perchlorate is sodium perchlorate. 